3PT counter weight causing low hydraulic loader pressure?

[MrZukerman]

A friend of mine bought a used kubota 35 hp tractor with factory loader, can’t recall the model of hand. He has always complained the fuel doesn’t have much lift capacity so took it to a local guy that repairs hydraulic cylinders and stuff to have it looked at and was told the the 1200 lbs or so three point counter weight he is using is taking the biggest part of the available hydraulic pressure to keep raised that the loader doesn’t have enough left over to lift much weight. Anyone else have any experience with this type of issues?

 

[ptsg]

It was important for us to know the exact model so we could know the diagram of the hydraulics.

Usually the loader valve is one of the first valves in the circuit with the remotes and 3 pt valves coming after. So anything after the loader valve, shouldn't really affects how the loader behaves.

Another possibility is a clogged screen or filter in the suction side of the pumps and it's not actually anything to do with the 3 pt.

 

[SPYDERLK]

Typically the 3pt is not using fluid after it has risen to set position. If there is a slow leak in the holding circuit it will leak down a bit and then again use fluid to regain the correct height. Faster leak - more frequent correction. These corrections would affect the fluid available to the loader. .. But there is the possibility of a fast "leak" through the 3pt relief valve because the weight is too heavy to be lifted to the correct position. Does the engine run free and easy when the weight is on the ground, but exhibit constant load when the weight is lifted? This would indicate a problem to investigate.

 

[WranglerX]

"Local Guy" does not know much about hydraulic and 3PH..... One could put stay/check chains on 3PH/Ballast and take load off hydraulics and problem will still exist..... I use use stay/check chains on ballast just to keep it from creeping down so I don't have to worry about ballast when using loader....

 

[MrZukerman]

I was able to ask my buddy what tractor model it is I knew that would be ery beneficial when i first posted but just didn’t remember. It’s a kubota L3300 and LA480 loader.

 

[oldnslo]

I was able to ask my buddy what tractor model it is I knew that would be ery beneficial when i first posted but just didn’t remember. It’s a kubota L3300 and LA480 loader.

If Kubota used a series - parallel type loader valve then trying to lift a load with loader and 3 point simultaneously would limit lift capacity of both. Reason for this is that with series spool on loader the return oil from lift cylinders is directed into the power beyond port feeding the 3 point so any load created by 3 point trying to lift would limit loader lift.

Kubota used this type of valve so can lift load and dump simultaneously or lower and curl. Again not sure if that tractor has this type of valve or not.

Other than that feature a load on 3 point should have zero influence on the loader.

 

[SPYDERLK]

I was able to ask my buddy what tractor model it is I knew that would be ery beneficial when i first posted but just didn’t remember. It’s a kubota L3300 and LA480 loader.

My L's have an adjustable damper valve that can be used to keep the 3ph raised. That should prevent the weight dropping from a possible leak in the height position control system. Check him about any engine loading holding a lifted weight suspended. There should be no apparent loading after the weight reaches set height. If there is, see if lowering it a tad stops the loading. .. Theres an adjustment to correct that issue.

 

[Tx Jim]

I suggest to check adjustment of 3pt hitch feedback rod to be sure 3pt control valve returns to neutral position after 3pt reaches it's desired height. As others stated 3pt piston seal could be faulty.

 

[TORQUIN]

As others have mentioned, a 3 point does not use any hydraulic pressure when it isn't moving up. If it leaks down a bit, it will automatically correct back to the set height, but that is momentary.
Look for another issue in the system. Perhaps a hydraulic filter, or even changing the fluid. I had a NH TC25 my buddy brought me because the FEL wouldn't lift, would lift sporadically, or was just super slow to move.
The 3 point was jumpy, but would slowly lift to the necessary height. A filter change did not fix it, but a fluid change made it all better. The old fluid was a bit milky due to water intrusion.

Chris

 

[Fxfymn413]

As I read the original post it looks like he is not satisfied with the lift capacity, not the speed. The rated lift capacity for the L3300 is 1058 pounds. Which is not all that much if he is trying to lift a bucket full of crushed stone, etc.

Get a hydraulic gauge and check the pressure of the system to ensure it meets factory spec and adjust the relief valve shims if doesn't.

Others are correct; the reasoning of the 3PH being a culprit is BS.

 

[Robert walker]

Typically the 3pt is not using fluid after it has risen to set position. If there is a slow leak in the holding circuit it will leak down a bit and then again use fluid to regain the correct height. Faster leak - more frequent correction. These corrections would affect the fluid available to the loader. .. But there is the possibility of a fast "leak" through the 3pt relief valve because the weight is too heavy to be lifted to the correct position. Does the engine run free and easy when the weight is on the ground, but exhibit constant load when the weight is lifted? This would indicate a problem to investigate.

I have a Kubota L3400DT. If I pull the lever on my 3 pt all the way up you can hear the engine strain a little and also you can tell the hydraulic pump is having to work. I can push forward on the lever just 1/4-1/2” and the engine goes back to normal and then my front end loader starts functioning correctly.

 

[SPYDERLK]

I have a Kubota L3400DT. If I pull the lever on my 3 pt all the way up you can hear the engine strain a little and also you can tell the hydraulic pump is having to work. I can push forward on the lever just 1/4-1/2” and the engine goes back to normal and then my front end loader starts functioning correctly.

Perfect!
I dont have that tractor, but, typical to L's is an external linkage, sensing position of the rocker shaft arms. This sensing element can be adjusted so that the 3ph does not dead head at its maximum height, but "automatically" stops just short of that position. Thats what we want to prevent the dead head power sapping condition you describe. The adjustment is quite sensitive and if you adjust it when the 3ph is unladen, crowding it toward MAX height capability, youre liable to get a surprise when you put a heavy implement on. The high lift force required introduces enuf flex that the sensor linkage doesnt quite relay the stop message. -- Its good to be alert to this condition.

​

 

[JBF43]

I have a Kubota L3400DT. If I pull the lever on my 3 pt all the way up you can hear the engine strain a little and also you can tell the hydraulic pump is having to work. I can push forward on the lever just 1/4-1/2” and the engine goes back to normal and then my front end loader starts functioning correctly.

You beat me to this suggestion as my L3130 does the same thing.

 

[old and tired]

Adjust #220, nut...

 

[careyo63]

Relief height Valve. 3Pt. lift arms. Set it before the Arms hit the Lifting Height limit. Dead Head! Relieves the pressure and what you should be hearing Squeal. Yanmar setup. Adjust it next to the lower fender. Shaft and lock nuts!

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[SPYDERLK]

It would be good to hear from the op again.